The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO4 3-; P) or potassium phosphonate (PO3 3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.
The objective of this study was to determine phosphorus effects on drought stress-induced oxidative stress in Kentucky bluegrass. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (P) or potassium phosphonate (PA). Application of phosphorus was efficient to ameliorate the adverse effects of drought. Osmotic potential, total chlorophyll and carotenoid content were significantly decreased by drought stress, but was relieved by P or PA application. Superoxide (O2 •−) concentration was significantly increased more than 14-fold under drought-stressed plants, was accompanied with increase of hydrogen peroxide (H2O2) and lipid peroxidation (MDA). However, malondialdehyde (MDA) was much less in P or PA applied plants under drought stress condition. Activities of catalase (CAT), ascorbate peroxidase (APX) and guaiacol-peroxidase (GPX) were largely increased by drought stress and its increase rate was much higher in P or PA applied plants except APX. These results indicate that drought stress-induced oxidative stress is alleviated by P or PA application due to the increase of activities of antioxidant enzymes.
한국산 점톨물방개속(Hydrovatus Motschulsky)의 분류학적 연구를 수행하였다. 2종이 발견되었으며, 노랑점톨물방개(H. acuminatus Motschulsky)를 국내에서 처음 보고한다. 본 속의 각 2종에 대한 성충의 외형 사진 및 식별 형질과 검색표를 제시한다.
한국산 꼬마검정물땡땡이속(Paracymus Thomson)의 분류학적 연구를 수행하였다. 꼬마검정물땡땡이속, 염전꼬마검정물땡땡이[P. aeneus (Germar)]와 꼬마검정물땡땡이(P. zaitzevi Shatrovskiy)를 한반도에서 처음 보고한다. 종에 대한 성충의 외형 과 주사전자현미경 사진, 분포도, 식 별 형질 및 검색표를 제시한다.
한국산 깨알물방개속(Laccophilus Leach)의 분류학적 재검토를 수행하였다. 한국에서 기록된 5종 중에서 L. hyalinus (De Geer), L. lewisius Sharp (줄깨알물방개), L. minutus (Linné) (대륙깨알물방개)는 각각 L. vagelineatus Zimmermann (얼룩깨알물방개), L. lewisioides Brancucci (줄무늬깨알물방개)(신칭) and L. difficilis Sharp (깨알물방개)의 오동정이다. 각 종에 대한 외형 사진, 주사전자현미경 사진, 검색표 및 식별형질을 제시한다.
The larvicidal and repellent activities of 33 plant extracts against two mosquitoes as Culex pipiens and Aedes albopictus were examined using direct contact application for larva and a patch test for adult. Chrysanthemum zawadskii var. alpinum, Cnidium officinale, Ginkgo biloba, Magnolia kobus, and Magnolia denudate at 1,000 ppm caused 100% mortality to Cx. pipiens larva within 24 hr. Ailanthus altissima, Dryopteris crassirhizoma, Houttuynia cordata, Mentha arvensis, Phyllostachys nigra, and Parthenocissus tricuspidata showed over 90% mortality to Cx. pipiens. C. zawadskii var. alpinum, C. officinale, G. biloba, M. kobus, M. denudate, and P. nigra gave 100% mortality at 1,000 ppm to Ae. albopictus. Acorus gramineus, Campanula takesimana, and D. crassirhizoma, showed 97.8%, 94.5%, and 94.4% mortality to Ae. albopictus at 24 hr, respectively. Five plant extracts (C. zawadskii var. alpinum, C. officinale, G. biloba, M. kobus, and M. denudate) showed 100% mortality both Cx. pipiens and Ae. albopictus. However, A. altissima gave 90% larvicidal activity to Cx. pipiens, whereas 7.8% mortality to Ae. albopictus. Several plant extracts which have highly larvicidal activities, were determined repellency against two mosquitoes species.
The Gyrinidae are water beetles with very unique lifestyle - adult rapidly gyrate and whirl on surface of water hunting for prey. They are found in stagnant or slowly running water and prefer clean oxygen-rich habitats. Members of the family are characterized by the following characters: compound eyes divided completely with one pair on the dorsal surface of the head (above the water line) and another on the ventral surface of the head (below the water line); antenna short with a broad, cup-shaped scape, subtriangular pedicel and elongate but compact flagellum; meso –and metathoracic legs broadly expanded and fringed with setae for swimming.
In this paper, a taxonomic review of the Korean Gyrinidae Latreille is presented. Seven species in three genera are recognized, one of which (Gyrinus pullatus Zaitzev) is reported for the first time in South Korea. We also discovered that G. curtus Motschulsky previously recorded in Korea was misidentification of G. japonicus Sharp. Habitus photographs, keys, redescriptions, and diagnostic characters with illustrations of the species are provided. The specimens used in this study are deposited in Chungnam National University Insect Collection (CNUIC), Daejeon, Korea.
Repellency of 20 plant essential oils to malaria main vector in the Republic of Korea (ROK), Anopheles kleini, was evaluated using skin direct contact bioassay. Anopheles kleini showed the highest repellency to Pelargonium graveolens with EC50 value of 0.244 mg/cm2, followed by Pinus sylvestris and Cinnamomum camphora with EC50 values of 0.484 mg/cm2 and 0.862 mg/cm2. The lowest repellency of An. kleini was revealed from Clary sage oil with EC50 value of 4.665 mg/cm2. Anopheles kleini did not demonstrated any repellency to Lemon, Orange, Neem, Coconut and Olive oil over 20 mg/cm2. Major repellent constituents of Geranium, Pine and Camphora oil were analyzed and identified using Mass-data, GC and GC-Mass. Major constituent of Geranium were β-citronellol (37.0%) and Camphora, 1,8-cineole (35.8%) and Pine, α-terpineol (39.5%). Anopheles kleini showed higher repellency to β-citronellol and 1,8-cineole than to DEET and IR3535 and did not showed any repellency to sabinene and γ-eudesmol over 20 mg/cm2. Residual repellent time of 1,8-cineole and β-citronellol were 26 and 41 min, respectively and DEET, 84 min and IR3535, 102 min. In the light of global efforts to reduce the level of highly toxic synthetic repellents, the three essential oils and their major constituents described merit further study as potential biorepellents for the control of An. kleini populations
A theoretical model is applied to the analysis of thermomechanical properties of FGMs in this study. Functionally graded composites ( FGMs) consisted with 10 layers gradually changing volume fractions of Al and were fabricated using the pressureless infiltration technique. FGMs plates of total thickness of 3mm, 5mm and 7mm with fairly uniform distribution and compositional gradient of reinforcement in the Al matrix throughout the thickness was successfully fabricated. The curvature of FGM plates was measured to check the internal stress distribution predicted via a theoretical model for the analysis of thermo-mechanical deformation. The evolution of curvature and also internal stresses in response to temperature variations could be predicted for the different combinations of geometric thickness of FGM plates. Theoretical prediction of thermally induced stress distribution makes it possible to design FGM structures without any critical failure during the usage of them.
The turtle leg (Pollicipes mitella), which belongs to the family Pollicipes, is widely distributed in the rock along the shore areas of the southern sea, Jeju island and Ulleungdo island of Korean Peninsula. Generally, the size, type, stripe pattern, and color of this species vary in accordance with water depth, turbidity, nutrition, growth period, water temperature, and other environmental aspects. Genomic DNAs were isolated from 21 individuals of three turtle leg (P. mitella) populations of Tongyeong, Yeosu and Manjaedo located in the southern sea of the Korean peninsula. After incubation, we added 300 l of 3 M NaCl, and gently pipetted for a few minutes. 600 l of chloroform was then added to the mixture and inverted (no phenol). The DNA pellets were then incubation-dried for more than 10 hours, maintained at -40℃ until analysis, then dissolved in the ultra-pure water. The concentration of the extracted genomic DNA was measured by its absorbance ratio at 260 nm, with a spectrophotometer (Beckman DU 600 series, UK). Seven primers were exposed to generate the unique loci to each population and number of shared loci by the three populations of turtle leg which could be clearly scored. The hierarchical clustering tree was analyzed by the similarity matrices to generate a dendrogram using pc-package program Systat version 10. As regards average bandsharing value (BS) results, the higher fragment sizes (>1,200 bp) are much more observed in the Yeosu population. The number of unique loci to each population and number of shared loci by the three populations generated by PCR using 7 decamer primers in the turtle leg (P. mitella) population of Tongyeong, Yeosu and Manjaedo. Genetic distances among different individuals of the Tongyeong population of the turtle leg (lane 01~07), Yeosu population of the turtle leg (lane 08~14) and Manjaedo population of the turtle leg (lane 15~21), respectively, were generated using the CLASSIFICATION option in Systat version 10 according to the bandsharing values and similarity matrix. Tongyeong population could be evidently discriminated with the other two Yeosu and Manjaedo populations among three populations. The longest genetic distance (0.305) was found to exist between individuals' no. 02 of the Tongyeong population and no. 13 of the Yeosu population. It seems to the author that this is a result of a high degree of inbreeding in narrow region for a long while. Three turtle leg (P. mitella) populations can be clearly distinguished, especially, by their morphological characters and PCR-based approach.